Mini Implants in Anterior Mandible: Expectations of Longevity?

Anon. asks:

I have been restoring implants for 6 years. I had never placed one because of the complexity of the anatomy and the armamentarium. However, I have now taken courses for mini implants and have placed them in sawdust mandibles. This is quite a bit simpler, than conventional implants, and requires far less equipment. I am thinking of restricting my use to the anterior mandible for supporting overdentures. I am concerned about longevity. For those of you actually doing this, what are your expectations for longevity? What, if any, complications have you experienced in placing these implants?

27 thoughts on “Mini Implants in Anterior Mandible: Expectations of Longevity?

  1. I have been placing these implants for 6 years. Survival rates up to one year have been around 90%, all immediately loaded. For fixtures that have survived 1 year, all have survived. However, some patients, especially those who had a knife edge ridge in the mandible that we did not flatten, have lost up to 30% of the initial crestal bone. This is the minority of patients, and most have lost far less than this.

  2. these alloy implants never integrate, failure rates are too high compared to standard tested fixtures, unskilled clinicians should always reflect a flap to see ridge, flatten and prepare sites. if adequate width, traditional fixtures with documented long ter success should be used, warrantees are there from manufacturers.minis failtoo often then what to do,replace for free, companies dont replace

  3. I have been placing Minis for about 8 years. I would suggest the more aggressive threads, use a stent, and check your osteotomy with a perio probe before inserting. I have done all of this and still I get failures. I would estimate about 80% success. Also it is ideal to make sure that the minis are not off angle since it will wear out the O rings too fast. Be selective to your cases and prewarn the pt that conventional implants have a higher success rate. When they work you have done a great service. When they fail others can be placed or switch to conventional. I tell my patients that if the mini fails I will do it again if they want but they will have to pay even if it only lasts a few months. I make them sign this agreement.

  4. Placing standard fixture implants in the anterior mandible is a procedure that any clinician who performs dentoalveolar surgery, should be able to perform with a success rate in the high 90′s. Using the mini implants as a substitute for them is a disservice to the patient.

  5. Minis were built as transitionals…eventhough they have been FDA approved, I would stay away from them for for restorations. Theybwill never be adequate to support a full denture for long term use.

    I have friends that have placed them and they are continually seeing more bone loss and usually have 1-2 minis break within 2-5 years. The companys say no big deal when this happens and to put another one next to the broken one. To get ideal functionality and great clinical results then you hve to place a lot of them side by side which increases your cost and us a lot more work.

    Larger implants give more support….period! Physics will back up that statement. Do the right thing for your patients…give them the proper treatment they deserve.

    The FDA should be ashamed of themselves for letting this slip by….however it is obviously not the first thing to slip by them.

    To end thus discussion…would you feel more safe driving on a bridge that is supported by toothpicks or by 8×8 pillars?

  6. I’ve been placing implants for 24 years with very good success rates. Vey rarely a failure. I tried “mini’s” for mandibular overdentures along with one of my associates. Most in good jaws. We’ve both stopped placing them. We experienced too many failures. Absolutely followed the manufacturers protocal and were very careful to avoid surgical complications. Had to replace them with standard implants when this occured. I can’t explain the reason for our failures when others are touting their success rates. We have a lot of surgical experience. But as a caution I will say working blind if you are inexperienced can lead to surgical errors and immediately loading them in function without rigid splinting does seem to violate the principles that we have followed for successful osseointegration.

  7. I first started to use minitransitional implants about 14 years ago, when Victor Sendax, who accidentally discovered the minitranstional implant philosophy, decided to use Dentatus Titanium posts that were intended for use in restoring endodontically treated teeth; and used them to help out the late Luciano Pavorotti, when an exisitng conventional fixed bridge failed because of rotted natural abutment teeth. He was able to place these titanium posts into the edentulous areas and drilled holes through the pontics of the bridge and stabilized the bridge.

    Bernard Weisman, the owner of Dentatus, worked with Sendax, and was the first company to coin the term Mini Transitional Implants.

    As the name suggests, their purpose was really intended to be used as a transitional proceedure until a more definitive solution was found.

    These narrow diameter implants ( initially 1.8mm in diameter) turned out to be so beneficial because of the simplicity of the surgery, and the ease of inserting them, and the fact that were immediately loaded…..contrary to the Branemark philosopy.

    Initially, they were made from pure surgical grade titanium, and in my esperience, even if they did achieve some degree of osseointegration, there was always the risk of fracture, because of the softness of the titanium.

    Several implant companies have picked up on these small diameter implants, have increased the diameter, and have made them from titanium alloy.

    Dentatus has an Atlas Kit, that allows the minis to be placed non parallel, whereby the retention is via a silicone lining inserted into the trough cut into the existing denture.

    I would agree with some of the above comments, in that given the choice, I would prefer to use a narrower conventional implant with conventional prosthetic options in situations requiring absolute osseointegration, and not take the risk…….but minis have their place, and the patients have to be informed of their limitations.

    Gerald Rudick dds Montreal, Canada

  8. I am alarmed to see so many of experienced surgeons refraining from mini implants as overdenture abutments. I have worked under a prosthodontist for 3 years and i have known him for 10years, he has been using Mini Implants for supporting overdentures with more than 95% success. i have a case lined up in 2 weeks, and now i am tensed whether to go ahead.
    If please anyone can guide me what precautions to take apart from Informed Consent from patients, it will be useful for me…

  9. It is surprising to hear statements that “mini dental implants dont integrate”, specially coming from an oral surgeon!

    Another interesting statement “Minis fail too often”. Probably in your hands!

    If you look at the surface treatment of a mini dental implant (not all of them but most reputable brands) you will find that the surface is sand blasted and acid etched, the alloy is titanium CpV (stronger), then the question if you got more than 35 nw of primary stability would be Why wouldnt they integrate? if all the conditions are there?

    Our experience with minis (and we use from 1.8 minis to 6.5 wide implants, has been extremely good.

    Of course we have had failures, every system does have failures.
    But in the anterior mandible the success rate is even better than that of regular implants.

    There is always the same issue here, why do some people get extremely good results and some others dont?

    Biomechanics- surface area- primary stability- prosthetic knowledge etc.

    Most people placing minis have not taken a course for minis, and minis are very technique sensitive, there are a lot of specific considerations to be respected.
    Dont expect to be the super surgeon and shift to minis and have success, in minis the advantage is to the one with the knowledge in applied loads.

    Go back to the book of Dr Mish (contemporary implant dentistry and read the biomechanics chapter, then translate that to a thinner device and to strategies to distract and divert the forces to the ridges and soft tissues instead to cantiliber the whole denture from the minis)

  10. It must be understood that inspite of the Mini’s being touted as an easy system for implant placement ..their placement is actually very technique sensitive
    The branemark protocol does NOT apply
    For example the MDI (Imtec) protocol has the following clearly stated protocols (variations will apply )
    There are many other steps but the following come to mind as examples of differences and common mistakes
    1) Always attempt bi cortical fixation
    In case of ant mandible go to within 3mm of inferior border

    In some cases minis can engage lingual plate to get the bi cortical fixation
    Maxillary cases engage sinus floors
    2)Drill with first and only drill thru cortex only ..less than one third the length of implant..do not drill to full depth
    b) very slow application of force thru finger driver to advance Mini
    DO NOT use torque wrench until last couple of threads and do 0.25 turn every 30 seconds
    3) Extreme care for prosthetic design
    In over dentures if the denture is not retrofitted and put back into occlusion as before (use bite registration) you are making a 12 unit fixed bridge on 4 tooth picks .. which WILL fail
    Implants” retain” the denture not support it ..this is the most common mistake we make
    In fixed cases you need to be very comfortable with Biomechanics of prosthetic design (previously reffered to text by Misch is excellent)

    At the end of the day titanium will integrate but every engineered design will have limitations ..we simply must learn the designs

    There is also a tendancy to abuse the minis as we feel they are so simple they are not worthy of our specialised expertise ..I can understand that having been thru the learning curve ..but for precisly the reason that they are so small and simple they need our utmost attention .
    I also understand that mini implant sales world wide are 50% of all implants sold ..sound high but I bet its not far wrong

  11. Thank you very much Dr sengupta & Dr Alvaro – both of you have infused confidence in me now, i also understand that everyone has to go thru the learning curve, I am going ahead with the case and have planned to place 4 mini Imtec implants supporting the lower denture… shall keep posted about the progress.

  12. I am happy to hear that!
    keep in touch I believe you have access to my personal email!

    As for the players, I have to admit I have been placing imtec mini implants since they became available in the market at the end of the nineties and I am extremely happy , but before that I got in 1994 a mini implants kit in Brasil, “Diamond” (no comments).

    I believe the actual top players in the market with quality products would be: Imtec, Dentatus, Sterngold and Intralock. There are more systems available in the market, maybe way so many.

    The Sterngold system would be the one different to the other ones since the attachment system is different with some advantages and disadvantages over the other three.

    Talking about which one has been available longer of the four systems in question? The evidence I have collected demonstrate that the Dentatus system was the initial system used by Dr Sendax.

    I hope this helps.

  13. I can only agree that mini implants are actually much much more difficult to place than conventional implants and because they are placed using flapless surgery it makes them even more difficult. They are not an easy option as people think.

  14. Thanks for the info of all of you pioneers out there. I just got into the “mini implant” ball game and am having a case coming up : FLD RETAINED by 4 or 5 Imtec MDI… “Retained, NOT supported” seems to be a most important factor to avoid failure of the MDI.
    So my quesstion is, should we process both dentures first, go through all the routine until the patient is completely comfortable, painfree with the new prosthesis… then place the implants and retrofit the denture. That way , all the adjustment and removal of the acrylic do not inadvertently turn the retainers into supporters.
    Please help!

  15. Mini dental implants are here to stay. I prefer to use 2.5 mm diameter mini or small or reduced diameter implants. They generally mean the same. Most are made of Titanium alloy and therefore are less prone to fracture than implants made of pure titanium. Also, because they are solid implants and not hollow like all conventional 2 piece implants, they are arguably less likely to fracture when compared to 2 piece implants where the thickness in some places may be barely 1.0mm. They are definitely dental implants because they are implanted into the jawbone to carry prosthetic teeth. If they are placed in bone and torqued to 35 to 50 ncm and to a depth of 10mm to 15mm, they should be very successful. The flapless technique used requires proper pre-planning with clear xrays, palpation with your trusty gloved finger and probing with a long probe after drilling into the bone to full depth to ensure that it is in solid bone and no vital structure is compromised. If the bone is prepared with care and with generous irrigation, the healing osseointegration with the mini implant is rapid and may bypass the margin of necrosis phase. The small size of the implant allows the surrounding bone to have overwheming healing advantage which may allow healing that is virtually inflammatory free. Placing a large conventional implant done with an open flap with sutures definitely increases the possibility of infection, compromises the blood supply and provokes a lot of inflammatory exudate that all serve to slow down the healing process. This may explain why minis can be loaded immediately if the insertion torque is at least 35ncm. Try to make sure the implants are parallel to each other as that will make the prosthodontic stage easier. I use both conventional and minis and often in the same patient especially in places where bone may be insufficient or the patient’s budget dictates. In all cases, explain carefully to the patient the treatment plan and get a signed consent. Most of my cases have been very successful and minis definitely have a place in dental implantology and maybe more and more so in the future.

  16. Dr Chow
    Thank you for your synopsis
    I have one question regarding your surgical protocol
    You say that you drill to full depth..I thus have to assume you not use the MDI system
    The protocol with MDI is that you drill no more than one third the length of the implant
    Namley you simply decorticate the site (unless bone is very dense)
    The rational being to acheive the Sendax term of “autointegration”
    The MDI is self tapping and is guided by the turning of the implant which is in the operators hands .
    Are you also drilling to full depth in the maxilla?
    I am curious as to which of the systems advocates the protocol you describe
    The osteotomy procedure per se removes bone
    I would in my experience have difficulty obtaining the requisit torques for many of my placements if I drilled to depth
    Thank you

  17. Dear Dr S.Sengupta,
    I use the MDI and MDL and other mini implant systems. The MDI protocol is suitable for soft bone, but medium bone onwards may be a problem. I drill to full depth in most cases because most bone is not homogeneous. It may be hard …then soft and then hard again because of different degree of calcification of the trabeculae. When I drill just past the cortex or even to a depth of 1/3 the planned depth, the dental implant often tends to veer off course and I end up in a direction that is less than ideal. Also, trying to parallel the implants to each other becomes a problem. I find that drilling to full depth allows me to not only insert the implant in the exact direction that I want it to, I also get it to the exact depth I plan it to. As long as my last drill is at least 1.0mm smaller in diameter to the intended implant, I get a very good insertion torque and therefore final primary stability. The name of the game is precise placement and parallelism as far as possible and the prosthodontic phase becomes a breeze.
    Cheers.

  18. I do not understand, what would be an indication to place mini implants as a permanent solution? If its a medical issue and conservative approach is in order, then placing mini implants flaplessly may turn out way more invasive than conventional implants. Especially, when the minis fail and now you need additional surgeries. If it is a bone issue, and you want to avoid grafting, and you can’t get in a narrow platform conventional implant, then doing a mini implant without direct bony visualization is the last thing you should be doing. If it is a financial issue, more often than not, the final treatment ends up being way more expensive for the patient after the minis fail and the case has to be salvaged with conventional implants. So why just not go the conventional route from the start. As far as placing implants into anterior edentulous mandible for an overdenture, it could get quiet challenging surgically, especially in atrophic cases where the bony anatomy is not what it seems. Placing the minis blindly and flaplessly could cause some serious problems. I believe the high failure rate is associated with the minis placed outside or very minimally into the jawbone because of not elevating the flap. Furthermore, injury to structures in the floor of the mouth, could result in serious intra and postoperative complications.

  19. I hope I do not offend too many proponents of mini-implants but I must speak my mind on this as mini implants should not be used as long term solutions and represented to the patients thus. I use them regularly to support provisional bridges and bone grafts. In every case you can back them out 6 months later with finger reverse torquing. Regular implants cant even when used under similar circumstances. Mini-implants are not permanent and are at best interim solutions.

    Again the issue of flapless surgery is oversold to younger implant dentists. Use this techniques only when you are absolutely sure of the underlying anatomy and when there is no need to reposition keratinised mucosa or when the mucosa is not too thick. Blind drilling never gives ideal results

  20. They work. Period. My dermatologist has a single porcelain crown on a mini implant, lower anterior, placed in 1994 in Maryland while he was a still in medical school. I know one anecdotal case does not mean anything, but try to convince me that mini implants “don’t work” and you will fail. I have placed several hundred now in the past five years, mostly for implant stabilization of lower dentures, but also for upper palateless dentures and fixed crown and bridge. Yes, some fail. Fixing the failures is simple and inexpensive because of the minimal bone destruction during placement, so I do it at no charge. Many, many patients are now functioning with lower teeth which do not dislodge during function who led miserable lives before the introduction of mini implants. Don’t let prejudice keep them from enjoying their lives. The FDA made the correct decision. Live with it.

  21. If you really want to see why some mini implants fail and some succeed, just look at a CT scan of some you have placed. Like any implant, they must be fully imbedded in good bone. Due to the local availability of CT, I have now begun requiring a scan prior to placement of any implant. A before and after scan removes almost any possibilty of unanticipated failures.

  22. Is the ability to back out mini-implants an advantage or a disadvantage. Think! As long as the mini-implant is not unscrewed, it stays stable and carries the crown or bridge more than adequately and does not come loose if all the basic principles of placing an implant in sound bone and to a good primary stability and torque are followed. The ability to unscrew most of them at will is a fantastic advantage especially in cases where you want to remove them or reposition them for whatever reason. Of course they are not permanent in the true sense of the word like all our conventional crowns and bridges, even though we used to call them permanent. In the same way, we really cannot call conventional implants permanent. The advantages of mini-implants are many……simple to use, require less bone volume, minimal bleeding and rapid healing, affordable to the majority of patients etc. I use both conventional and minis as required and I go flapless for both as far as I can.

  23. My addition to the discussion may be worthwhile.
    In the mandible I use Maxillary Mini implants. The design makes sense to me and I also drill deeper then the recommendation because of the thread design. I also do not load them for 3 months. I have had to remove some because of prosthetic change and could not back them off and they had to be cut. Small diameter implants are here and like any restorative method…..used correctly.
    I suppose some of you are using composite on posterior teeth. I was told that would not work either.

  24. Dear All,
    There are few situations that you should solve with mini implants.
    Extreme cases for over denture ( no teeth on the antagonist Jaw).
    Place 4-6 mini implants. (Even for this cases I would prefer Cylindir implants). The only case I safely use mini implants are congenitally missing laterals (incisors). and another case perhaps very narrow rige (implant for every single tooth). Or You can insert to somebody whose doctor says this person has only two months left. Sad isn’t it?

  25. A balanced approach is important. While some have suggested the use of mini-implants as economical solutions to those requiring teeth or in extreme conditions of bone deficiency, or as an interim or short term solution, there are proponents who claim that mini-implants are suitable for all indications.

    As I said I use mini-implants as part of overall armamentarium but can you really say that in a distal extension case in a bruxer, the use of mini-implants is superior? Or that it can provide you ideal emergence contours in a wide ridge when there is adequate width?

    My main contention is that it should not be represented to patients or younger dentists starting on implants that it is the treatment of first choice.

    On the use of flapless surgery, I have always been an advocate as part of minimal access surgery but to represent that it is the best option used 9 times out of 10 is again incorrect. It should be used when one is sure of the underlying anatomy and when there is no need to reposition attached mucosa. So a minimal flap rather than no or large flaps is my preferred approach. The flap design is an important part of long term clinical success. I would encourage the younger dentists to build experience on more conventional surgical approaches before modifying techniques as one gains a better feel of bone and surgical anatomy. To enter implant surgery via the flapless route only is not prudent.

    On the use of CT – cone beam CTs have much less radiation and one can argue for its routine use. If it is computered tomography I would hesitate on routine use before or after treatment as the radiaiton is pretty high to justify its use in every case. Having said that, I would insist on a CT in less predictable cases. A fair estimate of my use of pre-op CTs is probable 1 in every 3 cases, of which a small fraction of this would require a subsequent CT to check. This latter group will be to ascertain the success of the graft especially in the anterior maxilla. So again routine use of CT is something which perhaps should be approached with caution (unless perhaps one is referring to cone beam CT)

  26. Hi,
    Dr William Chong ,
    why is it distasteful if it works well even in patients that are heavy bruxers.
    Well osseointegrated minis worked well in narrow ridges and if it can do that it most assuredly worked in ridges with adequate bone.
    The main reason for failures is when one uses the standard approach of drilling to length as in placing the std and large diameter implants.
    Use the auto advancing technique and you will get integration in the upper 90percentile range.

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